.development-chapter {
  margin: 42px 0 30px;
  overflow: hidden;
  border: 1px solid #46525a;
  border-radius: 18px;
  background: #161b1f;
}

.development-chapter summary {
  position: relative;
  display: grid;
  gap: 7px;
  min-height: 118px;
  padding: 25px 70px 25px 28px;
  cursor: pointer;
  list-style: none;
  background: linear-gradient(135deg, #1b2226, #15191c);
}

.development-chapter summary::-webkit-details-marker { display: none; }
.development-chapter summary:focus-visible { outline: 3px solid #ffcc16; outline-offset: -5px; }
.development-chapter summary::after {
  content: '+';
  position: absolute;
  right: 28px;
  top: 50%;
  display: grid;
  width: 36px;
  height: 36px;
  margin-top: -18px;
  place-items: center;
  border: 1px solid #65727a;
  border-radius: 50%;
  color: #ffcc16;
  font-size: 23px;
  line-height: 1;
}

.development-chapter[open] summary::after { content: '−'; }
.chapter-kicker { color: #8b7cff; font-size: 11px; font-weight: 800; letter-spacing: 1.35px; }
.development-chapter summary strong { font-size: 25px; line-height: 1.25; }
.chapter-summary { color: #c7cfcc; font-size: 14px; }
.chapter-action { color: #86e5bd; font-size: 13px; font-weight: 750; }
.development-chapter[open] .chapter-action { font-size: 0; }
.development-chapter[open] .chapter-action::after { content: 'Close the chapter'; font-size: 13px; }
.chapter-body { padding: 30px 28px 32px; border-top: 1px solid #3b454b; }
.chapter-intro { max-width: 72ch; color: #d9dfdc; font-size: 18px; }
.platform-key,
.milestone-meta { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }
.platform-key { margin: 24px 0 34px; }
.platform-chip,
.knoq-chip,
.map-chip {
  display: inline-flex;
  align-items: center;
  min-height: 30px;
  gap: 7px;
  padding: 4px 10px;
  border: 1px solid #526068;
  border-radius: 999px;
  background: #20272b;
  color: #e9ece9;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: .2px;
}

.device-mark {
  position: relative;
  display: inline-block;
  width: 10px;
  height: 16px;
  border: 1.5px solid currentColor;
  border-radius: 2.5px;
}

.device-mark::after {
  content: '';
  position: absolute;
  bottom: 1px;
  left: 3px;
  width: 2px;
  height: 2px;
  border-radius: 50%;
  background: currentColor;
}

.knoq-chip { border-color: #6c6443; color: #ffcc16; }
.map-chip { border-color: #37644f; color: #86e5bd; }
.platform-note { color: #aeb8b4; font-size: 12px; }
.app-timeline {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: appmilestone;
}

.app-timeline li {
  position: relative;
  padding: 22px 22px 20px;
  border: 1px solid #364148;
  border-radius: 14px;
  background: #1b2124;
  counter-increment: appmilestone;
}

.app-timeline li::before {
  content: counter(appmilestone, decimal-leading-zero);
  position: absolute;
  top: 17px;
  right: 18px;
  color: #68757b;
  font-size: 12px;
  font-weight: 800;
}

.milestone-meta { margin-bottom: 13px; padding-right: 30px; }
.milestone-meta time { color: #ffcc16; font-size: 12px; font-weight: 800; }
.app-timeline h3 { font-size: 18px; }
.app-timeline p { margin: 0; color: #d0d6d5; font-size: 15px; line-height: 1.65; }
.trade-mark-note {
  max-width: 90ch;
  margin: 28px 0 0;
  padding-top: 22px;
  border-top: 1px solid #364148;
  color: #aeb8b4;
  font-size: 12px;
  line-height: 1.65;
}

@media (max-width: 780px) {
  .app-timeline { grid-template-columns: 1fr; }
  .development-chapter summary { padding: 23px 64px 23px 23px; }
  .chapter-body { padding: 25px 23px 28px; }
  .development-chapter summary::after { right: 20px; }
}

@media (max-width: 420px) {
  .development-chapter { border-radius: 14px; }
  .development-chapter summary strong { font-size: 22px; }
  .chapter-body { padding: 23px 18px 25px; }
  .app-timeline li { padding: 20px 18px; }
  .platform-note { flex-basis: 100%; margin-top: 3px; }
}

@media print {
  .development-chapter { border: 1px solid #888; background: #fff; }
  .development-chapter summary { padding: 16px; background: #fff; }
  .development-chapter summary::after,
  .chapter-action { display: none; }
  .chapter-body { display: block !important; padding: 18px 0; border-top: 1px solid #999; }
  .app-timeline { grid-template-columns: 1fr 1fr; }
  .app-timeline li { border: 1px solid #aaa; background: #fff; }
  .app-timeline p,
  .chapter-intro,
  .chapter-summary,
  .trade-mark-note,
  .platform-note { color: #222; }
  .chapter-kicker { color: #222; }
}